• Structural Engineering and Mechanics
• /
• 제61권3호
• /
• pp.335-345
• /
• 2017

Free vibration analysis for continuous bridge under any number of vehicles is conducted in this paper. Calculation strategy for natural frequency and mode shape is proposed based on Euler-Bernoulli beam theory and numerical assembly method. Firstly, a half-car planar model is adopted; equations of motion and displacement functions for bridge and vehicle are established, respectively. Secondly, the undermined coefficient matrices for wheels, vehicles, intermediate support, left-end support and right-end support are derived. Then, the numerical assembly technique for conventional finite element method is adopted to construct the overall matrix of coefficients for whole system. Finally, natural frequencies and corresponding mode shapes are determined based on iterative method and overall matrix solution. Numerical simulation is presented to verify the effectiveness of the proposed method. The results reveal that the solutions of present method are exact ones. Natural frequencies and associate modal shapes of continuous bridge under different conditions of vehicles are investigated. The influences of vehicle parameters on natural frequencies are also demonstrated.

• 한국자동차공학회논문집
• /
• 제19권6호
• /
• pp.76-81
• /
• 2011

Fossil fuel, the energy source of internal combustion engine automobiles, is limited in resource and has caused environmental issues for decades. Accordingly, automobile manufacturers from many countries around the world are developing or producing eco-friendly vehicles that utilize alternative sources of energy. These vehicles are equipped with many electronic and electrical components which operate on high voltage and/or large current that were not used in conventional combustion engine automobiles. In this paper, in order to analyze the electro-magnetic interference noise, electric vehicles and fuel cell electric vehicles are tested under the guidelines of KMVSS (Korean Motor Vehicle Safety Standards) as well as under test modes that are not stipulated under the guidelines.

• 한국군사과학기술학회지
• /
• 제15권5호
• /
• pp.543-549
• /
• 2012

Hybrid electric propulsion systems are expected as future primary combat platforms because the systems can supply enough electric power, easily locate components inside vehicles, and maneuver without undesired noise. However, increasing electric/electronic/software usage causes abnormal failure patterns which have not been noticeable in conventional automotive. Recently, the functional safety standard for road vehicles were enacted and vehicle manufacturers request their components which satisfy standardized quality. This research analyzes functional safety standards(IEC 61508 and ISO 26262) and compares the standards for road vehicles with military standards of system safety. Strategies to apply functional safety in the combat hybrid electric vehicle are scrutinized.

• 자동차안전학회지
• /
• 제14권4호
• /
• pp.21-26
• /
• 2022

Commercial use of autonomous vehicles is to come soon. So far most of responsibility of the accident is on the human driver with conventional vehicles whereas that will be on the car OEM and transportation related organizations with autonomous vehicles, which asks car OEM's and government to do vast study of car crash in various conditions. Test protocols need amendment and to be newly enacted to reflect new findings from the study aforementioned. Rigid stationary barrier and moving or stationary deformable barrier as well as car to car test which is same as actual accident can be utilized to simulate the crash happening on the road. Among those 3 test methods, rigid stationary barrier is most economic and has good repeatability. Limitation as well as advantage of the rigid stationary barrier is studied through comparison between car to car crash and oblique rigid barrier crash.

• 디지털융복합연구
• /
• 제21권1호
• /
• pp.9-13
• /
• 2023

저탄소 자동차가 미래의 자동차 시장을 주도할 것으로 인식되고 있지만, 기존 내연기관 자동차보다 높은 가격과 관련 인프라 부족 등의 장애물로 인해 보급 확대에 여전히 많은 어려움이 있습니다. 본 연구는 아시아 선진국과 자동차 시장의 성숙도를 앞선 한국과 일본의 저탄소 자동차 판매현황과 정책대응을 비교한 것이다.본 연구의 결과는 차세대 저탄소 자동차의 미래 방향에 대한 학계 및 관련 산업 및 정책적 시사점을 제공하는데 목적이 있다.

• International Journal of Automotive Technology
• /
• 제8권6호
• /
• pp.781-790
• /
• 2007

Hybrid electric vehicles(HEV) combined with more than one power sources have great potential to improve fuel economy and reduce pollutant emissions. The Integrated Starter Generator(ISG) HEV researched in this paper is a two energy sources vehicle, with a conventional internal combustion engine(ICE) and an energy storage system(batteries). In order to investigate the potential of diesel engine hybrid electric vehicles in fuel economy improvement and emissions reduction, a Dynamic Programming(DP) based supervisory controller is developed to allocate the power requirement between ICE and batteries with the objective of minimizing a weighted cost function over given drive cycles. A fuel-economy-only case and a fuel & emissions case can be achieved by changing specific weighting factors. The simulation results of the fuel-economy-only case show that there is a 45.1% fuel saving potential for this ISG HEV compared to a conventional transit bus. The test results present a 39.6% improvement in fuel economy which validates the simulation results. Compared to the fuel-economy-only case, the fuel & emissions case further reduces the pollutant emissions at a cost of 3.2% and 4.5% of fuel consumption with respect to the simulation and test result respectively.

• 전기의세계
• /
• 제24권6호
• /
• pp.85-91
• /
• 1975

A new design method for the SCR-Chopper type speed controller of the battery-powered vehicles was developed. The conventional speed-controllers were either inductance type or contact type using resistance. In the new method, a photocoupler was used in sensing the control currents and a noncontacting type photo-conductive device (CDS) was used in mading acceleration. Experiments using these new devices showed encouraging results.

• 전력전자학회:학술대회논문집
• /
• 전력전자학회 1998년도 Proceedings ICPE 98 1998 International Conference on Power Electronics
• /
• pp.938-943
• /
• 1998

The induction motor of the electric vehicles is controlled based on the vector control method to obtain good torque control characteristics. In the conventional vector control system, the field exciting current should be kept on a constant value to keep a stable flux level. This method has a liability that core loss becomes increasing at the light load region. To solve this liability, the efficiency maximizing control method of the vector controlled induction motor is proposed in thid paper. We developed light weight water cooled 60kW induction motor drive system which adopts our method and fabricated a conversion electric car for actual vehicle test. We demonstrate the usefulness of drive system by comparing its driving mode with conventional field oriented system and an efficiency maximizing controlled induction motor.

• 월간포장계
• /
• 통권348호
• /
• pp.80-85
• /
• 2022

• 한국멀티미디어학회논문지
• /
• 제15권8호
• /
• pp.996-1003
• /
• 2012

본 논문은 차량용 전방 카메라를 이용하여 근거리 옆 차선의 차량을 검출하는 방법을 제안한다. 근거리 옆 차선의 차량은 상대적 위치에 따라 형태의 변화가 심하기 때문에 기존의 방법들은 대부분 움직임 정보를 이용하여 근거리 옆 차선 차량을 검출한다. 그러나 이러한 움직임 정보에 기반한 방법들은 자가 차량을 앞지르는 차량만 검출할 수 있다는 문제가 있다. 이러한 문제를 해결하기 위해 제안하는 방법은 움직임 정보를 사용하는 대신 근거리 옆 차선 차량이 존재하는 관심 영역의 특징을 이용한다. 이로 인해 근거리 옆 차선의 추월 차량 뿐 아니라 정지해 있거나 나란히 주행하는 차량들 또한 검출이 가능하다. 실험 결과, 제안하는 방법은 다양한 날씨 및 도로 환경에서 근거리 옆 차선 차량을 효과적으로 검출하였으며 실시간 처리 속도를 보여주었다.